Lymphocytic choriomeningitis virus has been found to produce a destructive retinopathy following intracerebral inoculation into the newborn rat. Employing such methods as virus titration, serology, fluorescent antibody histochemistry, and routine histopathology, these studies will attempt to clarify the pathogenesis of factors responsible for the development of intraocular disease of viral etiology. The possibility that this may be an immunopathologic disease will be studied with immunosuppression of the infected animals employing antilymophocyte serum and cyclophosphamide. The pathogenicity of other members of the arenovirus group for ocular tissues will also be assessed.